A speaker diaphragm employed in a speaker requires a high Young's modulus and moderate internal loss in order to reproduce high-quality sounds from the speaker.
FIG. 17 is a perspective view of a conventional speaker diaphragm. In FIG. 17, speaker diaphragm 204 is configured with laminated body 203 including inorganic fiber fabric 201 and natural fiber nonwoven fabric 202 laminated on the bottom face of inorganic fiber fabric 201. This speaker diaphragm intends to achieve excellent characteristics in both Young's modulus and internal loss by attaching inorganic fiber fabric 201 that has low internal loss but high Young's modulus and natural fiber nonwoven fabric 202 that has low Young's modulus but high internal loss. This technology is disclosed in Patent Literature 1.
However, aforementioned conventional speaker diaphragm 204 is configured by simply attaching inorganic fiber fabric 201 and natural fiber nonwoven fabric 202, which have different natures. Therefore, inorganic fiber fabric 201 and natural fiber nonwoven fabric 202 are not sufficiently integrated. Accordingly, a high Young's modulus of inorganic fiber fabric 201 and high internal loss of natural fiber nonwoven fabric 202 are not fully demonstrated, failing to sufficiently improve the speaker sound quality.    Patent Literature 1: Japanese Patent Unexamined Publication No. 2003-219493